Conformable apparatus in a drill string

Abstract

An apparatus in a drill string comprises an internally upset drill pipe. The drill pipe comprises a first end, a second end, and an elongate tube intermediate the first and second ends. The elongate tube and the ends comprising a continuous an inside surface with a plurality of diameters. A conformable metal tube is disposed within the drill pipe intermediate the ends thereof and terminating adjacent to the ends of the drill pipe. The conformable metal tube substantially conforms to the continuous inside surface of the metal tube. The metal tube may comprise a non-uniform section which is expanded to conform to the inside surface of the drill pipe. The non-uniform section may comprise protrusions selected from the group consisting of convolutions, corrugations, flutes, and dimples. The non-uniform section extends generally longitudinally along the length of the tube. The metal tube may be adapted to stretch as the drill pipes stretch.

The invention claimed is: 
     
       1. An apparatus in a drill string, comprising: an internally upset drill pipe comprising a pin end, a box end, and an elongate tube intermediate the pin and box ends, the elongate tube and the ends comprising a continuous inside surface with a transition region a comprising a locking surface in both the pin end and the box end; a conformable metal tube disposed in a position within the drill pipe intermediate the ends thereof terminating adjacent to ends of the drill pipe; wherein the conformable metal tube substantially conforms to the continuous inside surface. 
     
     
       2. The apparatus of  claim 1  wherein the metal tube is more corrosion resistant than drill pipe. 
     
     
       3. The apparatus of  claim 1  wherein the metal tube has a rough outside surface. 
     
     
       4. The apparatus of  claim 1  wherein the metal tube is expanded to conform to the drill pipe using hydraulic pressure. 
     
     
       5. The apparatus of  claim 1  wherein the metal tube is expanded inside the drill pipe by being drawn over a mandrel. 
     
     
       6. The apparatus of  claim 1  wherein the apparatus comprises an insulating material between the metal tube and the inside surface. 
     
     
       7. The apparatus of  claim 6  wherein the insulating material resists galvanic corrosion between the metal tube and the inside surface. 
     
     
       8. The apparatus of  claim 1  wherein the metal tube is adapted to stretch with the drill pipe. 
     
     
       9. The apparatus of  claim 1  wherein the metal of the metal tube is selected from the group consisting of steel, stainless steel, titanium, aluminum, copper, nickel, chrome, and molybdenum, or compounds, mixtures, and alloys thereof. 
     
     
       10. The apparatus of  claim 1  wherein the metal tube comprises a non-uniform section expanded to conform to the inside surface of the drill pipe. 
     
     
       11. The apparatus of  claim 10  wherein the metal tube has a regular end portion that is free of the non-uniform section. 
     
     
       12. The apparatus of  claim 10  wherein the non-uniform section comprises protrusions selected from the group consisting of convolutions, corrugations, flutes, and dimples. 
     
     
       13. The apparatus of  claim 10  wherein the non-uniform section extends generally longitudinally along the length of the elongate tube. 
     
     
       14. The apparatus of  claim 10  wherein the non-uniform section extends spirally along the surface of the tube. 
     
     
       15. The apparatus of  claim 10  wherein the non-uniform section is intermediate regular end portions of the metal tube. 
     
     
       16. The apparatus of  claim 10  wherein the non-uniform section is formed using hydraulic pressure. 
     
     
       17. The apparatus of  claim 10  wherein the non-uniform section is formed by roll forming or by stamping. 
     
     
       18. The apparatus of  claim 1  wherein one or more dies are used to form the non-uniform section of the tube. 
     
     
       19. The apparatus of  claim 1  wherein inside surface comprises a transition region forming a convex region and a concave region in the inside surface. 
     
     
       20. The apparatus of  claim 19  wherein the concave region comprises a resilient ring.